1. Technical Field
The present invention relates to a protection structure of a battery module mounted in the rear of a vehicle body.
2. Related Art
These days, in the automobile industry, an electric vehicle and a hybrid electric vehicle that have a high output battery module mounted in a vehicle body and runs with stored electric power of the battery module are developed.
In Japanese Unexamined Patent Application Publication (JP-A) No. 2012-006519, the battery module is disposed between a pair of left and right rear side frames provided in the rear of the vehicle body. In this case, for example, when a following vehicle body running behind the vehicle body collides with the vehicle body, the following vehicle body collides with the rear end of the rear side frame, and the rear side frame is compressed along an axial direction with an applied force. With this, it is possible to absorb an impact at the time of the collision.
However, in the case where the battery module is provided in the rear of the vehicle body as in JP-A No. 2012-006519, it is possible to absorb the impact with the axial compression of the rear side frame when the following vehicle body collides with the rear end of the rear side frame as described above, but there are cases where the following vehicle body is a large vehicle such as, e.g., a truck or the like and the large vehicle body collides in an overriding state in which the large vehicle body is offset in an up and down direction relative to the rear side frame.
In the collision in the overriding state in which the vehicle body is offset in the up and down direction, the following vehicle body does not collide with the rear end of the rear side frame. As a result, the rear side frame is not compressed in the axial direction with the applied force at the time of the collision, and there is a possibility that the following vehicle body of which the impact is not absorbed moves into the vehicle body to reach a mounting position of the battery module.
To cope with this, in a conventional vehicle body, the battery module mounted in the rear of the vehicle body needs to be formed to have a size and a shape that do not allow the battery module to protrude above the rear side frame. As a result, the capacity of the battery module mounted in the rear of the vehicle body is limited. Realistically, it is difficult to adopt a structure in which a large-capacity battery module protruding above the rear side frame is mounted in the rear of the vehicle body by appropriately utilizing a space in the rear of the vehicle body such as a trunk or the like.
Thus, in the vehicle body of an automobile or the like, it is desired to relieve the limitation on the capacity of the battery module while securing collision safety performance of the battery module mounted in the rear.